Add concept of a transparent or null adjustment layer to Photoshop

I appreciate the concept of using smart layering to handle filters but it does not go far enough, especially if one wants to add several filters but mask their effect differently. I hate duplicating layers because this makes images less maintainable over time and I know others who feel the same.

I think it would be really great to have the concept of a transparent adjustment layer that acts as a pane of glass over all the layers below it (similar to After Effects) to which one can target one or more filters. Those filters will act on the sum of the image layer(s) and adjustment layers (if any) under in the same way painting on a pane of glass affects one's view of the scene on the other side.

The beauty of this approach is that one could target filters and mask them separately if one desires!